Apparatus and method for detecting pipelwe defects

ABSTRACT

An apparatus and method are disclosed for scanning and detecting defects in sewer and similar pipelines that eliminate the need to stop and pan-and-tilt areas of concern. In the method of the invention, a pipeline ( 15 ) inspection probe ( 10 ) of the apparatus of the invention comprising a CCD camera ( 14 ) with fish-eye lens ( 12 ) travels through the pipeline ( 15 ) on a self-propelled tractor automatically collecting data and transmitting it to a computer to provide a real-time display of the pipeline ( 15 ) interior with quasi three-dimensional information for effective and quick data analysis and management. The data includes digitized forward views and unfolded 360 degree laid-flat side-san ( 22 ) views of the pipeline ( 15 ) interior. Additionally, the digitized data may be stored for further analysis, tabulation, and for use with pipeline infrastructure maintenance software.

RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional PatentApplication No. 60/207,784, filed May 30, 2000.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to apparatuses and methods for inspectingthe interior of conduits and pipes, particularly pipelines, such assewers, air ventilation ducts, or liquid or gas transport pipelines, andlocating defects such as corrosion, joint separations, cracks,depressions, or crushes in same, as well as roots, debris, blockages,and the like. More specifically, this invention relates to viewingdevices and methods for movably scanning the interior of pipes orpipelines and to the collection of data for analysis and interpretationof the results of such scanning to evaluate the condition of thepipelines and the location of any defects in the pipelines.

[0004] 2. Description of Relevant Art

[0005] As used herein, the term “pipeline” or “pipelines” shall beunderstood to include conduits, pipes, and ducts as well as pipelinesand other such lines for transporting storm or sanitary sewage, air,liquids, gases or slurries. Known systems for inspecting pipelinestypically comprise a television camera or a video camera mounted on aself-propelled electric tractor or on a sled pushed by a semi-rigidcable along the pipe from an open end of the pipe. Lights are attachedto illuminate the pipeline interior. Both the lights and the camera arepowered by the cable. An image of the pipeline is captured by the cameraand recorded by a VCR (video cassette recorder) for viewing. Thestandard mode of operation employs pan, tilt and zoom capabilities bythe camera. A forward looking view down the center of the pipeline istypically displayed and recorded, unless the operator stops to take acloser look—to pan, tilt and zoom—at a particular area of the pipeline.The taking of a closer look is dependent on the operator's subjectivejudgment during the inspection. If the operator, for whatever reason,does not visually identify an area of potential interest or concern(cracks, roots, etc.) in the forward looking view, the opportunity tostop, pan, and tilt to get more detailed information is lost. If asubsequent view of the video tape alerts another viewer to a potentialproblem area, detailed information can only be acquired by reinspectingthe pipeline.

[0006] Common problems with known commercial systems have includedinability to accurately gauge the location of a detected defect,insufficient lighting to identify a defect, distortion of image,inadvertent missing of defects, uneven quality and subjective defectclassification, and requirement for burdensome review of volumes ofvideo tapes after the inspection in an effort to decipher the videotapes and to distinguish defects from shadows. Most typically, use ofknown commercial systems can result in oversight of critical cracks andother defects in the pipeline.

[0007] Canadian patent application no. 2,216,800 of Core Corp. generallydiscloses or suggests a device using a beam of light reflected off of arotating mirror said to provide a 360 degree round image of a pipeline.However, this device does not appear to include a digital forward viewof the pipeline.

[0008] There continues to be a need for improved methods and apparatusesfor fast, accurate and economical inspection of pipelines and evaluationof data associated with same.

SUMMARY OF THE INVENTION

[0009] An apparatus and method is disclosed for inspecting or scanningthe interior of a sewer line (or other similar pipeline) that eliminatesthe need for and consequent delay associated with stopping for pan andtilt closer inspection and that provides objective inspection. Moreover,an apparatus and method is disclosed that provides a real-time digitizedand synchronous forward view and a 360 degree peripheral or side-scanview of a pipeline. The continuous digitized real time images may besaved for later evaluation.

[0010] The apparatus of the invention comprises a probe with an opticalviewer or visual sensor, such as for example a video or CCD (chargedcoupled device) camera (or preferably a 3CCD camera, and as used hereinwith respect to the invention, the terms optical viewer or visual sensoror camera shall be understood to include without limitation any and allof these various kinds unless specifically indicated to the contrary)with a fish-eye lens (or other lens capable of performing a similarfunction of viewing in wide angles), a mover for carrying the probe intoand out of the pipeline, such as for example a self-propelled tractor, alight or light source, such as for example at least one ring of LEDlights, a power supply for the light source and for the camera, adistance measurer, an inclinometer, gyroscope and/or other location ordirection detector, data processing software and a computer for runningsaid software and for collecting, digitizing, and manipulating the data,displaying the results, and saving the data for further analysis,further evaluation, or for use with pipeline infrastructure maintenancesoftware as desired.

[0011] The data processing software of the apparatus of the inventionshould have the capability of performing the data processing steps inthe method of the invention, and the computer of the apparatus shouldhave sufficient memory and processing power to store and manipulate thedata collected. For most applications contemplated, the computer(including computer display) portion the light, the optical sensor, thedistance measurer, and the location, direction, or orientation detectoror detectors will be sent into the pipeline for data collection oracquisition. Connection between the probe and the computer is preferablymade through appropriate cabling for transport of data to the computer,although it is anticipated that wireless communication may be possiblein some applications. Connection is also made between the probe and apower source.

[0012] In the method of the invention, a probe comprising, or havingassociated therewith, a light or light source, a visual or opticalsensor or viewer (such as for example a video or CCD, or preferably a3CCD camera, and as used herein with respect to the invention, the termsoptical viewer or visual sensor or camera shall be understood to includewithout limitation any and all of these various kinds unlessspecifically indicated to the contrary) having the ability to view wideangles, preferably about 360 degrees, such as with a fish-eye lens orwide-angle lens, a distance measurer, and a direction, orientation orother location detector, is obtained and transported into and movedthrough at least a portion of a pipeline whose interior is to beinspected. The probe must be sufficiently small to fit into and to bemoved through the pipeline to be inspected without damaging thepipeline. Preferably, the probe will also be comprised of materials thatwill not interfere with the operation of the pipeline. The probe isconnected to, or otherwise in communication with, a computer (which neednot be on the probe itself and preferably is located where at least thecomputer display can be viewed by persons on the surface and notthemselves in the pipeline.)

[0013] As the probe is moved through the pipeline, the optical sensor orvisual viewer scans (in about 360 degree views) the pipeline wall and atspecified intervals takes forward (or frontal) views and side-scan views(or forward views that will be digitized and processed to make unfoldedside-scan views) which are sent as output to the computer. At the sametime or substantially the same time as the views are being taken by theoptical sensor or visual viewer, the direction and location detector ordetectors is providing output to the computer concerning location of theprobe at the time of the scan, and such information preferably includesat least the angle of inclination and axial rotation of the probe. Alsoat the same or substantially the same time, the distance measurer isproviding information to the computer about the distance that the probeis in the pipeline. Preferably for sewer pipes, typically less thanabout eight to about twenty-seven inches in diameter, the side-scanviews (or forward views that will be digitized and processed to makeunfolded side-scan views) are taken about every one or two millimeters,and the forward views are taken about every 100 millimeters, of distanceinto the pipeline that the probe is traveling as it passes through thepipeline. Many other intervals may alternatively be used, depending onthe purpose or use (i.e., the type of liquids or gases the pipe maycarry) may influence the pipeline detail desired. Scans as frequently asabout every 0.1 millimeter are generally achievable.

[0014] The scans or taking of the views is preferably automatic andcontinuous, at whatever intervals selected, and thus full coverage ofthe interior surface of the pipeline is obtained (without need forsubjective decisions concerning any particular area of the pipeline).The probe is not stopped while the views are taken and the views aretransported as output to the computer for processing and preferablyreal-time display at the pipeline surface. Preferably, an operator atthe surface of the pipeline monitors the real-time digitized display forcomparison to the video picture from the optical sensor or video camera,also being displayed real-time. This comparison is preferably done toensure quality performance of the probe and the data processing.Typically and preferably, all or substantially all forward views takenare displayed, but fewer forward views are recorded and saved. (That is,many multiple forward scans that are digitized and processed to makeunfolded side-scan views are typically or preferably saved lessfrequently whereas the portion comprising the multiple side-scan linesin every forward view frame is preferably saved.) Although not necessaryfor the present invention, the actual picture from the optical sensor orvideo camera may also be recorded and saved if desired.

[0015] With equipment commonly available today, the views taken by avideo camera are in NTSC (National Television System or StandardsCommittee) video output format. This output goes into a frame captureboard for conversion from analog to digital data. (In the future, theoutput may instead be originally taken and transmitted in digital form).Pixel manipulation software then manipulates the digital data to obtainunfolded side-scan images of the pipeline interior. The unfoldedside-scan images of the pipeline are created by identifying the pixelsthat fall on a pre-specified sampling circle on each frame captured by aframe capture board and then correcting the data with the rotation angledata from the inclinometer. For faster scanning, more than one samplingcircle may be used (that is, the sampling circles may be used inmultiples). Inclinometer data is used to locate the direction of thepipeline bottom (or lowest point with respect to gravity) for “cutting”the side-scan image to “unfold” it (i.e., unscroll it or cause it to belaid-flat) for real-time visualization of the laid-flat pipe image. Theside-scan image could be cut and unfolded at other points of thepipeline than the bottom.

[0016] Further with respect to the preferred method of the invention,the digitized forward view and the digitized unfolded side-scan view maybe viewed simultaneously on the computer display in real-time as theprobe passes through the pipeline. Still further, the digitized viewsmay preferably be compared in real-time to the video picture beingtransmitted (also in real-time) from for use with pipelineinfrastructure maintenance software.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a cutaway schematic view of the pipeline inspectionprobe of the apparatus of the invention.

[0018]FIG. 2 is a schematic side view of the pipeline inspection probeof the apparatus of the invention with the light source separatedtherefrom for illustration.

[0019]FIG. 3 is a schematic side view of the pipeline inspection probeportion of the apparatus of the invention on a wheel type mover in apipeline (transparent for illustration) showing the location of the wideangle or fish-eye lens and the accompanying 360 degree radius of thesampling circle automatically taken by the apparatus.

[0020]FIGS. 4a-g provide a flowchart and schematic of steps forunfolding a side-scan image of a pipeline interior taken using theapparatus of the invention according to the method of the invention.

[0021]FIG. 5 is a photograph of a forward image of the interior of apipeline obtained using the invention.

[0022]FIG. 6 is a photograph of an unfolded side-scan laid-out flatimage of the interior of a pipeline obtained using the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

[0023] An apparatus and method are disclosed for scanning the interiorof a conduit, pipe or pipeline to determine defects in the interior ofsuch pipeline. Such “defects” as the term is used herein is understoodto include joint separations, corrosion, cracks, depressions, or crushesand the like in the pipeline, and even obstructions or projections (suchas roots or debris) and the like in or into the interior of thepipeline, and also any other visible feature, characteristic, orcondition of the pipeline that may be of concern or interest forinspection or determination. The pipelines suitable for inspection withthe apparatus and method of the invention are preferably positionedsubstantially horizontally or at least off of vertical. The advantagesof the invention may be especially appreciated with pipelines that areburied underground and with pipelines that transport liquids, gases, orslurries, such as sewer lines. Further, the advantages of the inventionmay be especially appreciated for inspection of pipelines that are toosmall in diameter or too hazardous to be entered by a person forinspection.

[0024] The apparatus and method provide a view of the interior wall ofthe pipeline from a scan view of the pipeline interior wall. The side orside-scan view is an “unfolded image”—a two-dimensional representationof a three-dimensional pipe which is equivalent to cutting the pipe andunfolding it and laying it out flat. This laid-flat or side-scan viewcan be displayed and digitally recorded simultaneously with the forwardview, which is also displayed and digitally recorded.

[0025] This side-scan view is made from a digitized 360 degree forwardview taken with a wide-angle or fish-eye lens (or other lens or opticalsensor or viewer capable of viewing wide angles) as depicted in FIG. 3,as will be further discussed below. As used herein, reference to takinga side-scan view shall be understood to refer to scanning the pipelineand taking visual information or data that will ultimately, afterprocessing, result in an unfolded side-scan image of the pipeline wallwhich may be displayed and digitally recorded. Forward views that areprocessed to make side-scan images are displayed and saved as forwardviews but preferably saved at a less frequent interval than side-scanlines.

[0026] The apparatus of the invention generally comprises two parts—afield data acquisition or collection part, also often called thepipeline inspection probe, and a data processing part, which is oftenreferred to as the control center or control unit comprising at leastone computer or data processor and software. At least the pipelineinspection probe portion of the apparatus is placed inside the pipeline.The control center portion is preferably outside of the pipeline andmost preferably on the surface above or near the pipeline.

[0027] An example of a pipeline inspection probe of the apparatus of theinvention may be depicted as shown in the schematic of FIG. 1, whichillustrates a cutaway view. This part of the apparatus of the inventioncomprises a probe or probe body 10, visual viewer or optical sensor 14,which is preferably a video or CCD camera or more preferably a 3CCDcamera, and associated lens 12, which is preferably a fish-eye lens. Thefish-eye lens 12 in or associated with the camera 14 enables the viewingof the forward views on sampling circle(s) on the pipeline interiorpreferably in wide angle (most preferably 360 degree) radius scans asshown in FIG. 3 as scans 22. Other lens that could accomplish thisresult could alternatively be used.

[0028] The apparatus of the invention further comprises a light or lightsource 18, which is preferably at least one and most preferably multipleLED lights which are preferably evenly spaced one with respect to theother, and an inclinometer (not shown), preferably a gyroscope orgyroscope sensor (not shown), and/or other device or devices (not shown)for providing information concerning the posture of the probe andtherefore the location and direction of the pipeline.

[0029] The camera 14, lens 12, and lights 18 (and other componentscomprising the probe 10 or on or attached to said probe 10 such thatsaid camera 14 and lens 12 may view the pipeline interior withoutobstruction from any other components of the probe and said lights 18may illumine the interior of the pipeline so that the views taken by thecamera 14 may be clearly seen.

[0030] Light is essential for high quality optical pipeline inspection.Light sources such as LED lights that provide a brilliant, stable,long-lasting light are preferred for use in the present invention.Halogen bulbs readily available today tend to be too unstable forpreferred use in the present invention. That is, the luminosity providedby halogen bulbs changes over time, and the luminosity provided byhalogen bulbs is not-uniform, i.e., the luminosity changes in directionfrom source. Moreover, halogen bulbs generate significant heat. Heatgenerated by the light source can cause large errors with optical videosensors like a CCD sensor and gyro sensors because such sensors have atemperature dependent drift nature. LED lights do not generate asignificant, if any, amount of heat. LED lights are also relatively longlasting when compared with halogen bulbs. The longer lasting the lightsource the better for the invention because bulb replacement can causedown time and field delays.

[0031] As shown in FIG. 1, the LED light source 18 of probe 10preferably has a ring shape. In one example embodiment, about 20 smallbut high luminosity LED lights are placed along the ring at a constantinterval. In another example embodiment, more than one ring is used, asshown in FIG. 1, which has 4 rings of about 24 LED lights. The exactnumber of lights needed will depend at least in part on the size of theprobe and the pipeline. These equally distributed LEDs realize a uniformluminosity in any direction from the optical sensor. This luminosity mayalso be easily adjusted by changing the voltage applied, a furtheradvantage of this invention.

[0032]FIG. 2 shows a schematic side view of probe 10 with the lightsource 18 separated or removed from the probe 10 to better illustratedetail of the light source 18. As shown in FIG. 2, the light source 18is preferably mechanically designed in such a way that a field operatorcan easily exchange the light source module 19 without reassembling themain part of the pipeline inspection probe 10. Thus, for example, if oneof the LEDs in or on the ring dies or ceases to emit light, the fieldoperator can exchange a “plug-in” light source module. The term“plug-in” as used herein is meant to be a generic term for any number ofmechanical embodiments or operations that allow for removal andreplacement of the light source module 19 onto the main body of probe10. This exchange feature of the light source of the system of thisinvention is particularly advantageous with pipeline inspection probesthat have been water-proofed, such as by filling with nitrogen gas. Thelight source may be replaced without disturbing the main body of theprobe or requiring its reassembly, and thus without interfering with anywater proofing of the

[0033] The apparatus of this invention also preferably has an improvedgyroscope sensor associated with the probe 10 or attached to the probe10 or the camera 14 for identifying the exact location and direction ofthe camera 14 in the pipeline which in turn allows for identity of theexact location of a pipeline defect seen with the camera. Morespecifically, the system of this invention and particularly the datacollection component of the apparatus of the invention preferably hasaccurate gyro sensors that measure pipeline deflection that isassociated with the location data.

[0034] Deflection of a pipeline may be measured in various ways; themost common three ways are with an accelerometer, with a magnetometer,or with a gyro sensor. Any of these could be used for the presentinvention, subject to the following limitations. The accelerometerdepends on gravitational field so that only vertical deflection can bemeasured. The magnetometer depends on the earth's magnetic field and sois affected by nearby subsurface and/or surface metal structures andconsequently is useless in metal pipes. The gyro sensor was originallydeveloped for fast moving objects such as airplanes, missiles, etc., andis thought to provide accurate data only when it moves relatively fast.However, for use with the present invention, we have discovered a way toeliminate noise from gyro data stored with time information thatenhances the use of gyro sensors, even at slower speeds more oftenpreferred for pipeline inspection.

[0035] The output of the gyro sensor is known to be angular velocity. Togenerate the angle of pipe, the angular velocity must be integrated withtime, and to generate deflection (trace) of pipeline, anotherintegration of the angle with distance is needed. When an object movesslowly like a pipeline inspection probe, the output of angular velocityis very small and heavily polluted by noise. When this data isintegrated to generate deflection, the noise is also integrated and thisenhanced noise can make the generated deflection meaningless, at leastas seen in the prior art.

[0036] However, we have discovered that when the main component of thenoise depends on the nature of the sensor, and when the conditions ofmeasurement such as temperature and speed of an object are fairlyconstant, then the noise is also fairly constant. The following two wayprocedure may then be used to eliminate the noise from the gyro datastored with time information.

[0037] In this compensation method for gyroscope data, gyro data ismeasured two ways—going forward in the pipeline and coming back throughthe pipeline. If the data has no noise, the generated final direction ofthe probe must be the same as the direction when it was at its startingpoint. If a difference is observed, then this difference in angle,called Theta-error, can be considered the integrated amount of noise.Noise generation speed, Theta-error/T, is calculated by dividing theTheta-error by the total time of measurement (T). Measured gyro data isrecalled with time information, Theta (t), where “t” is the time frombeginning of the measurement. The

Theta-c(t)=Theta(t)−Theta-error/T*t.

[0038] The pipeline trace (deflection) is then calculated by integratingthe compensated angle with distance.

[0039] For example, a computer simulated this correction or compensationfor gyroscopic data from a gyroscope sensor running from the left toright at the speed of about 20 mm/second. After the sensor reached thedistance of about 1000 mm, the sensor returned to the starting point.The total time of the measurement was 100 seconds (=1000 mm*2/20). Trueinclination was set at 10 degrees from 220 mm to 300 mm distance, at 5degrees from 320 mm to 400 mm, at −5 degrees from 620 mm to 700 mm andat −10 degrees from 720 mm to 800 mm. Supposing, for example, thatTheta-error after a round trip was 1 degree, then Theta-error/T was 0.01degree/second and Theta-c(t) was calculated by Theta-c(t)=Theta(t)−0.01*t for this case. The computer simulated data was then compared withreal data and satisfactory comparison was seen.

[0040] The apparatus of the invention also preferably has an automatedcamera vibration correction which uses the gyroscope data for a hardwarebased correction and has a software based correction which keeps thecenter of the pipeline in the same position on the output or datadisplay.

[0041] Referring to FIG. 3, the probe 10 may further comprise, beattached to, fitted with, or otherwise associated with, a mover formoving the probe through the pipeline 15. A preferred mover for theprobe 10 is a self-propelled tractor on which the probe rests and isattached. Other suitable movers include for example without limitationwheels 11 fitted directly onto or part of the probe. Alternatively, themover could be a sled or slide for sliding or pulling or pushing theprobe through the pipeline. In still another embodiment, the mover couldbe a cable for holding and pushing or pulling the probe. The mover maybe any means that effects such movement of the probe through thepipeline, which movement should preferably be smooth, steady, consistentand easily controlled. The mover should also preferably provide a stablesupport for holding the probe relatively steady during movement in andthrough the pipeline. Further the mover should also preferably becomprised of material that will not damage or interfere with the utilityof the pipeline, and should preferably operate in a manner, i.e.,provide movement to the probe through the pipeline, that will not damageor interfere with the utility of the pipeline. Further, the probe andthe mover should preferably be of sufficiently small size to haveutility in a broad spectrum of size ranges of pipe and to preferably beable to turn pipeline corners.

[0042] Alternative embodiments of this invention are foreseen where thepipeline has incorporated within it, permanently or semi-permanentlyinstalled, data acquisition elements of this invention such that a moveris not needed to move a probe and a mobile probe itself is not used tocontain

[0043] The apparatus of the present invention also preferably comprisesor has associated therewith a distance meter or measurer for measuringor determining the distance of the probe in the pipeline when thevarious views of the pipeline are taken. Such distance is needed todetermine where the probe and camera are and hence where in the pipelineany defects that are detected are located. Such distance measurer may bepartially on the probe and partially at the exterior surface of thepipeline but wherever located should preferably be able to providedistance information in real-time with the scan of the pipelineinterior. Distance measurement is typically made for or associated withthe side-scan image (or the forward view that will be processed to makethe unfolded side-scan image) by the camera. However, the particularmethod or equipment used to determine such distance is not critical solong as the determination is accurate.

[0044] One example of a distance measurer suitable for use in theapparatus of the invention is a winch comprising cable (not shown). Thelength of the cable will be determined by the need—the length of thepipeline to be evaluated—and availability. One example length that maybe typical is 1000 feet of cable but wide variation in the cable lengthis possible and expected. Such winch and cable are used for runningcable into the pipeline with the probe 10 for measuring distance of theprobe 10 in the pipeline.

[0045] A winch and cable may also be used for providing communicationwith the probe 10 for controlling direction of the probe 10, forproviding energy to the probe 10, etc., and for receiving informationand data back from the probe 10 and the probe 10 components such assensors and camera 14 to the control center (not shown). A controlcenter (or control unit) may be used or positioned on the surface orelsewhere outside the pipe in the field to provide a power supply to theprobe and to control the lights and the mover for the probe and also toreceive and store data received back from the probe 10 or its various orassociated components. Alternative methods may be used to control and/orprovide energy to the probe and/or to receive data, including laser andinfrared technology. Most preferably, fiber optics or fiber optic cableis used to communicate with the camera 14 and particularly the fish-eyelens 12.

[0046] In the method of the invention, a pipeline inspection probe ofthe apparatus of the invention, or a data collection apparatus withsimilar capabilities as that of the apparatus of the invention,preferably automatically takes a forward view (or a forward view thatwill be processed to make an unfolded side-scan view) of the pipelineinterior as the probe (with camera) moves along the pipeline. (In analternative embodiment, the probe preferably automatically takesdigitized forward and side-scan views of the pipeline interior wall asthe probe (with camera) moves along the pipeline.) The exact periodicdistance for the scans will depend in part on the However, a practicaland typical (but not meant to be limiting) example distance for use ofthe invention in typical sewage pipelines is every ten centimeters (orone hundred millimeters) for the forward view and every one or twomillimeters for the side-scan view. The data collection apparatus alsotakes a reading of the angle of inclination and axial rotation of theprobe, preferably with each view or at least preferably with eachside-scan view.

[0047] The data processing part of the apparatus of the invention usesthis data to provide the field operator with a quasi-three dimensionalunderstanding of the internal view of the pipeline as well as of thedeflection of the pipeline (both vertical and horizontal deflection). Apreferred computer monitor display preferably provides the operatorsimultaneously with a forward-looking view in the pipeline, an unfoldedside-scan of the pipeline interior wall, and a compass or gyroscopedisplay of deflection as well as a data quality indicator. FIG. 5 showsan example forward-looking view that may be seen on the display and FIG.6 provides an unfolded side-scan image of a pipe that may be seen on thedisplay. The control center may also include a real time video, CD, DVD,or hard disk recording of the pipeline scan which may be displayedpreferably on another screen, such as a video or television screen, forcomparison with the display of the digitized forward-looking view.

[0048] In general terms, the display layout for the real-time digitizeddata collection of this invention can be understood by considering acylindrical coordinate system having an x-axis for the direction of thepipeline, a t-axis for the azimuth direction along the pipeline wall,and an r-axis for the direction perpendicular to the pipeline wall. A360 degree unfolded side-scan view provides a two-dimensional image ofthe x-t plane and a forward-looking view provides a two-dimensionalimage of the t-r plane. The forward-looking view gives the image wherethe data collection system is going to from now on, and the side-scanview gives the image where the data collection system has passed throughalready. The deflection of pipeline is indicated with both numbers(vertical inclination and horizontal meander) and a directional arrow(or other directional indicator) in a three-dimensional system. Dataquality indicators, such as roll angle of the data collection system,deviation from suitable speed, etc., allow the operator to maintain thedata collection (by the pipeline inspection probe) under suitableconditions or within preferred limits.

[0049] All of the raw data collected by the pipeline inspection probe orthe field data collection part of the apparatus of the invention is fedinto a computer programmed to digitize the data and outputs from thefield data collection part of the apparatus—at least the forward-lookingview, the distance and the direction of the field data part of theapparatus when taking the views—using data processing software,including the software outlined in the flowchart and schematics atFigures

[0050]FIGS. 4a-g outline the steps involved in analyzing andinterpreting the pipeline inspection probe data output to obtain aside-scan unfolded image of the pipeline interior at any particularpoint along the pipeline. Referring to FIG. 4a, NTSC video output datafrom a forward image scan with the field data acquisition part (thepipeline inspection probe) of the apparatus of the invention accordingto the method of the invention is transmitted to the data analysis andinterpretation part (the control center) of the apparatus of theinvention. In the control center, the analog data is converted todigital data on a frame capture board. Pixels that fall on apre-specified circle—the sampling circle—in each frame are identified,as schematically shown in FIG. 4b. The sampling circle is placed suchthat it is concentric to the center axis of the pipe—the point at thefar end of the pipe where the image seems to converge to a point. Thus,the sampling circle is located on the inner circumference of the pipeimage. The diameter of the sampling circle may be changed to adjust theview angle. The larger the diameter, the wider the view angle.

[0051] Using the inclinometer data, the bottom of the pipe isdetermined, as shown in FIG. 4c. The side-scan image could be cut andunfolded at other points of the pipeline than the bottom. The bottom,however, is the location most often containing debris and thus is thelocation that may consequently contain less helpful data and thus is thepoint thought most suitable for cutting for the unfolding of the image.

[0052] NTSC video output data of a forward view that will be processedas an unfolded side-scan view taken with the probe is transmitted to thecontrol unit and processed as depicted in the flowchart at FIG. 4d andin the schematic at FIG. 4e, showing a processed unfolded side-scanimage. Typically, one sampling circle is used. For faster scanning,pixels can be obtained on preferably two or more sampling circles anddrawn on the unfolded image—two or more lines for every frame with thevideo or CCD camera moving. FIG. 4f schematically depicts the procedurefor rearranging the pixels that are on the scan-ring line so that theyline up in a straight line with the bottom most two pixels at theopposing ends, to create an “un-folded” side-scan image. Finally, thetwo images—the forward view and the unfolded side-scan view—are shown onthe display in the control center at FIG. 4g. “Zooming” in on the viewspreferably should be available from the display. Also as illustrated inFIG. 4g, this digitized image data may be saved for later use,manipulation, or processing.

[0053] Other software needed for the data processing of the output fromthe pipeline inspection probe of the invention is commonly available andknown to those skilled in the art, such as software for convertinganalog data to digital data and software for manipulating pixels on aframe capture board, including software to obtain a forward view of thepipeline. Preferably, the preferably, all such collected digital datamay be saved and stored on electrical media such as CD, DVD, hard disk,or other storage media or method desired.

[0054] The data processing software selected for use in or with theinvention preferably should enable a quick search of specific data sets,replay of the data, and application of processing such as filtering. Thesoftware also preferably should allow an interpreter to putinterpretation or comments on the display or image, and/or to addinterpretive diagrams and statistics to the original data set.

[0055] The data set format provided by use of one embodiment of theapparatus and method of the invention is attached as an Appendix. Thesedata sets would allow one skilled in the art to use and manipulate thedigitized data output from the invention in any manner desired, such asfor further evaluation, tabulation, and use with pipeline infrastructuremaintenance software.

[0056] The foregoing description of the invention is intended to be adescription of preferred embodiments. Various changes in the details ofthe described method and apparatus can be made without departing fromthe intended scope of this invention as defined by the appended claims.

We claim:
 1. A method for detecting defects or damage in the interiorwall of a pipe or pipeline, comprising: obtaining a probe comprising orhaving associated therewith a light source, an optical sensor or viewercomprising a lens capable of viewing about 360 degrees, a directionlocator or location detector, and a distance measurer, wherein saidprobe is in communication with a computer or data processor forprocessing data from said probe; passing said probe through the interiorof said pipeline while illuminating at least a portion of said pipelineinterior wall with said light source and viewing and recording ortransmitting for recording views of said pipeline interior wall whereilluminated with said probe; recording said location and distance ofsaid probe in said pipeline as data for at least some of said views; andprocessing said recorded views and direction and distance data such thatsaid views are digitized and displayed in real-time as forward views andside-scan views and wherein said side-scan views are unfolded imagesshowing approximately 360 degrees of the pipeline wall.
 2. The method ofclaim 1 further comprising saving for later analysis said digitizedviews and data in a data file format suitable for images.
 3. The methodof claim 1 wherein said location and distance data comprises angle ofinclination and axial rotation of probe.
 4. The method of claim 1wherein said probe is returned through said pipeline after passingthrough said pipeline, said direction locator is a gyroscope or gyrosensor, and said direction locator data is recorded as the probe passesthrough the pipeline and as the probe is returned through said pipeline.5. The method of claim 4 wherein said direction data from said gyroscopeor gyro sensor is adjusted for noise according to the compensationmethod.
 6. The method of claim 4 wherein said direction is obtained frompipeline deflection calculated using gyroscope or gyro sensor data byintegrating the compensated angle with distance.
 7. The method of claim6 wherein the compensated angle is calculated using the followingformula: Theta-c(t)=Theta(t)−Theta-error/T*t where: Theta-error is thedifference in angle observed between gyro data measured as the probegoes forward and comes back through the pipeline; T is total time;Theta(t) is the time from the beginning of the measurement; andTheta-c(t) is the compensated angle.
 8. The method of claim 1 whereinsaid optical viewer is a video camera or a CCD camera.
 9. The method ofclaim 8 wherein said views are transmitted by the probe to said computeras analog data which is converted to digital data by said computer andwherein pixels are manipulated on a frame capture board to obtainreal-time digitized forward and side-scans views of the pipelineinterior.
 10. The method of claim 8 wherein said views comprise digitaldata that has been compressed and wherein said views are digitallytransmitted by the probe to said computer for display and storage. 11.The method of claim 8 where said views comprise digital data whosepixels are manipulated to obtain real time digitized forward andside-scan views of the pipeline interior.
 12. An apparatus for detectingdefects or damage in the interior of a pipeline comprising a pipelineinspection probe and data processing software that digitizes data fromsaid probe in real time, providing both forward and unfolded side-scanimages of the pipeline interior.
 13. The apparatus of claim 12 whereinsaid probe comprises a light source for illuminating the pipelineinterior and an optical sensor or camera comprising a fish-eye lens forobtaining forward and side-scan views in the pipeline.
 14. The apparatusof claim 12 wherein said software includes instructions for manipulatingthe pixels from the digitized views such that at least one samplingcircle is obtained for each frame of the forward view and successivescans can be concatenated so that the side-scan view may be displayed asan unfolded, laid-flat, side-scan image encompassing about 360 degrees.15. The method for detecting defects or damage in a pipeline comprising:passing the apparatus of claim 12 through said pipeline; taking forwardviews of the interior wall of said pipeline; digitizing and processingsaid views; simultaneously displaying digitized forward and side-scanimages in real time, wherein said side-scan images are unfolded 360degree images; and saving said images for further evaluation.
 16. Themethod of claim 15 wherein said pipeline is a sewer line or similarpipeline for transporting liquids, gases, or slurries.
 17. A method forobtaining real-time unfolded side-scan images of an interior pipelinewall substantially simultaneously or synchronously with forward imagesof the pipeline interior for use in inspecting the pipeline wall fordefects or damage, said method comprising: passing a lighted probecomprising a camera with a fish-eye lens through said pipeline obtainingforward or frontal views having about a 360 degree radius at periodicintervals; relaying said views in analog data format to a data processoror computer; converting said analog data to digital data; manipulatingpixels from said digital data on a frame capture board such that atleast one sampling circle is obtained for each side-scan view;displaying an unfolded 360 degree image of the side-scan view of saidinterior pipeline wall.
 18. The method of claim 17 further comprisingdisplaying substantially simultaneously with said side-scan image, aforward or frontal view said interior pipeline wall.
 19. The method ofclaim 17 wherein said side-scan views are recorded about every 0.01millimeter to about every 100 millimeters along the pipeline interiorwall and said forward views are recorded at least about every 10millimeters to about 1000 millimeters along the pipeline interior wall.20. The method of claim 17 wherein said pipeline is a sewer line andsaid side-scan views are recorded about every 1 or 2 millimeters alongthe pipeline interior wall and said forward views are recorded aboutevery 100 millimeters along the pipeline interior wall.
 21. The methodof claim 17 wherein said side-scan views are recorded more frequentlythan said forward views but where said side-scan views and said forwardviews are recorded synchronously.
 22. The method of claim 19 whereinsaid pipeline is a sewer line or similar line for transporting liquidsor gases or slurries.
 23. A method for detecting internal pipelinedefects or damage, comprising: passing a lighted probe comprising avideo camera with a fish-eye type of lens through at least a portion ofthe interior of said pipeline, illuminating said pipeline and recordingforward and side-scan images periodically and synchronously during saidpassing; noting simultaneously with said recording of at least saidside-scan images the location of the probe in the pipeline at the timeof recording of said image; and digitizing and processing said imagesfor display wherein said processing comprises pixel manipulation on atleast one line of a sampling circle to obtain an unfolded image of theside-scan view.
 24. The method of claim 23 wherein said pixelmanipulation is done on a frame capture board.
 25. The method of claim23 wherein said display includes both forward views and side-scan 26.The method of claim 23 further comprising saving said digitized imagesfor later evaluation or use.
 27. The method of claim 26 wherein saidimages are saved in a data file format for images.
 28. A pipelinescanner comprising a field data collection apparatus and data processingsoftware that allows a real-time forward view of the pipeline as well asan unfolded side-scan view of the pipeline walls.
 29. The scanner ofclaim 28 wherein said field data collection apparatus acquires aforward-looking view of the pipe interior and a 360 degree unfoldedside-scan view of the pipe interior surface together with information ondistance and direction of the apparatus in the pipe.
 30. The scanner ofclaim 28 wherein said data collection apparatus comprises an LED lightsource.
 31. The scanner of claim 28 wherein said data collectionapparatus comprises a camera with a fish-eye lens.
 32. The scanner ofclaim 28 wherein said data collection apparatus employs a compensatedmethod to correct for gyro sensor noise.